Poly(aryl ether ketone) block copolymers

ABSTRACT

Described are crystalline block copolymers displaying high glass transition temperatures, excellent mechanical properties, excellent chemical and thermal stability, and good melt processability. These block polymers contain segments of crystalline poly(aryl ether ketones).

REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of patent application Ser.No. 729,580 filed May 2, 1985.

FIELD OF THE INVENTION

This invention is directed to novel crystalline block polymersdisplaying high glass transition temperatures, excellent mechanicalproperties, excellent chemical and thermal stability, and good meltprocessability. These block polymers contain segments of crystallinepoly(aryl ether ketones). The invention is also directed to noveloligomers and to processes for the preparation of these oligomers, aswell as to processes for the preparation of the block polymers based onthese oligomers.

BACKGROUND OF THE INVENTION

Over the years, there has been developed a substantial body of patentand other literature directed to the formation and properties ofpoly(aryl ethers) (hereinafter called "PAE"). Some of the earliest worksuch as by Bonner, U.S. Pat. No. 3,065,205, involves the electrophilicaromatic substitution (e.g. Friedel-Crafts catalyzed) reaction ofaromatic diacylhalides with unsubstituted aromatic compounds such asdiphenyl ether. The evolution of this class to a much broader range ofPAE's was achieved by Johnson et al., Journal of Polymer Science, A-1,Vol. 5, 1967, pp. 2415-2427, Johnson et al., U.S. Pat. Nos. 4,108,837and 4,175,175. Johnson et al., show that a very broad range of PAE canbe formed by the nucleophilic aromatic substitution (condensation)reaction of an activated aromatic dihalide and an aromatic diol. By thismethod, Johnson et al. created a host of new PAE's including a broadclass of poly(aryl ether ketones), hereinafter called "PAEK's".

In recent years, there has developed a growing interest in PAEK's asevidenced by Dahl, U.S. Pat. No. 3,953,400; Dahl et al., U.S. Pat. No.3,956,240; Dahl, U.S. Pat. No. 4,247,682; Rose et al., U.S. Pat. No.4,320,224; Maresca, U.S. Pat. No. 4,339,568; Atwood et al., Polymer,1981, Vol. 22, August, pp. 1096-1103; Blundell et al., Polymer, 1983Vol. 24, August, pp. 953-958; Atwood et al., Polymer Preprints, 20, No.1, April 1979, pp. 191-194; and Rueda et al., Polymer Communications,1983, Vol. 24, September, pp. 258-260. In the early to mid-1970's,Raychem Corporation commercially introduced a PAEK called STILAN, apolymer whose acronym is PEK, each ether and keto group being separatedby 1,4-phenylene units. In 1978, Imperial Chemical Industries PLC (ICI)commercialized a PAEK under the trademark Victrex PEEK. As PAEK is theacronym of poly(aryl ether ketone), PEEK is the acronym of poly(etherether ketone) in which the 1,4-phenylene units in the structure areassumed.

Thus, PAEKs are well known; they can be synthesized from a variety ofstarting materials; and they can be made with different meltingtemperatures and molecular weights. The PAEKs are crystalline, and asshown by the Dahl and Dahl et al. patents, supra, at sufficiently highmolecular weights they can be tough, i.e., they exhibit high values (>50ft-lb/in²) in the tensile impact test (ASTM D-1822). They have potentialfor a wide variety of uses, but because of the significant cost tomanufacture them, they are expensive polymers. Their favorableproperties class them in the upper bracket of engineering polymers.

PAEKs may be produced by the Friedel-Crafts catalyzed reaction ofaromatic diacylhalides with unsubstituted aromatic compounds such asdiphenyl ether as described in, for example, U.S. Pat. No. 3,065,205.These processes are generally inexpensive processes; however, thepolymers produced by these processes have been stated by Dahl et al.,supra, to be brittle and thermally unstable. The Dahl patents, supra,allegedly depict more expensive processes for making superior PAEKs byFriedel-Crafts catalysis. In contrast, PAEKs such as PEEK made bynucleophilic aromatic substitution reactions are produced from expensivestarting fluoro monomers and thus would be classed as expensivepolymers.

In all of the above described U.S. Patents, the copolymers that aredescribed are random or ordered copolymers characterized in that all ofthe repeat units of the polymer are derived from monomers and aretypically distributed randomly along the polymeric chains.

European Patent Application No. 125,816, filed Apr. 19, 1984, based forpriority upon British patent Application No. 8,313,110, filed May 12,1983, is directed to a method for increasing the molecular weight bymelt polymerization of a poly(aryl ether) such as PEEK.

The process of European Patent Application No. 125,816, provides a basisby melt polymerization above the crystalline melting point of thepoly(aryl ether) to increase the molecular weight by chain extension ofpolymer blocks. The application theorizes that the procedure can be usedfor making the block copolymers described in U.S. Pat. Nos. 4,052,365and 4,268,635. Implicit problems associated in the process of thisapplication are the difficulty in controlling the molecular weight ofthe resulting polymer and/or limiting isomerization and the problemsassociated with branching. The process of this European applicationwould appear to be advantageous in making composites where the linearityand solution properties of the final polymer are not so critical.

PAEK block copolymers have been described in U.S. Pat. Nos. 4,052,365and 4,268,635. U.S. Pat. No. 4,052,365 describes random or blockcopolymers having repeating units of the structure --Ar--O--Ar--CO-- and--Ar--O--Ar--SO₂ --. The patent states that these block copolymers arecrystalline. U.S. Pat. No. 4,268,635 describes a process for preparingpolymers containing --Ar--O--Ar--CO-- and --Ar--O--Ar--SO₂ -- unitswhich the patentee believes to contain block structures. The patentstates that the polymers are crystalline and exhibit improved hightemperature properties compared with totally random copolymers ofsimilar composition. However, the block copolymers in said patentsrequire units with --SO₂ -- linkages. The --SO₂ -- linkage tends tobreak up the crystallinity of the polymer which results in inferiorproperties as compared to polymers which do not contain the --SO₂ --linkage but have ether and/or keto groups instead. Due to the amorphousnature of the sulfonyl containing component used in making these priorart block copolymers, lower rates of crystallization are induced andhence, their commercial utility is less than desirable. The --SO₂ --component so adversely affects the crystallinity properties that thereis a maximum limit in the T_(m), far below that for the block polymersof this invention. A further deficiency of these prior art blockcopolymers is that they cannot be used to form compatible blends withother PAEKs.

U.S. patent application, Ser. No. 729,580 filed on May 2, 1985, in thenames of R. A. Clendinning et al., titled "Block Polymers Containing aPoly(Aryl Ether Ketone) and Methods for Their Production", commonlyassigned, describes a family of novel aryl ether ketone blockcopolymers. The blocks of the subject patent application containessentially ether groups (--O--) joined to keto groups (--CO--) through1,4-phenylene groups. The block copolymers in question are toughmaterials, that are easy to fabricate; their thermal and chemicalresistance are excellent. However, their glass transition temperaturesare rather low for some applications; they are generally in the range ofabout 150° to about 160° C. In some applications, such as in compositesfor example, a highly stable and tough matrix having a high glasstransition temperature is required. This is due to the fact thatpolymers, even crystalline polymers, exhibit an excessive loss ofmodulus, strength and creep resistance above their Tg's. This loss inproperties may not be acceptable in cases where the materials are to beused as thermoplastic matrix resins. Hence, the preparation of poly(arylether ketones) combining their generally excellent properties with highglass transition temperatures is of great practical importance. Suchhigh Tg block and extended copolymers are described herein.

THE INVENTION

This invention comprises solution-polymerized block polymers wherein thecomponents of the block structure are tough, crystalline poly(aryl etherketone)s (PAEK's). The blocks contain essentially ether groups (--O--)joined to keto groups (--CO--) through units of the formulae (1), (2),(3) and/or (4). In addition to units (1), (2), (3) and/or (4), ##STR1##the ether (--O--) and keto (--CO--) groups may also be joined through1,4- or 1,3-phenylene groups (5). This invention is also directed tomonomers and oligomers which are suitable for making the blockcopolymers. Also, this invention is directed to methods for making themonomers, the oligomers and the block copolymers.

The introduction of units (1), (2), (3) and/or (4) was found to have adramatic effect upon the glass-transition temperature of the poly(arylether ketone) block and chain-extended copolymers. The higher the weightpercentage of units (1), (2), (3) and/or (4) in the copolymer, thehigher is its Tg. Unexpectedly, the effect of units (1), (2), (3) and/or(4) upon the crystallization behavior of the novel block and extendedcopolymers, is negligible.

The block polymers of this invention are tough, crystalline and have agood combination of physical and mechanical properties.

The block is bonded to another block of the same or differentcomposition through one or more of an ether group, a keto group, or adivalent copolymeric chain extending unit. In the case where the blocksare the same, bonding is effected through a divalent monomer, dimerunit, or oligomeric unit connecting the blocks through ether groups toproduce a copolymeric structure. In the preferred embodiment, with thepossible exception of when the blocks are connected through a divalentchain extending single unit, the poly(aryl ether ketone) comprisesessentially ether and keto groups joined through units of the formulae(1), (2), (3) and/or 4, and in addition, optionally through units (5).The block polymers of this invention preferably have a reduced viscosityof at least 0.9 dl/g as measured in sulfuric acid at 20° C.(concentration of 1 gm/100 ml).

The solution-polymerized polymers of this invention contain oligomericblocks that are interconnected. The oligomeric blocks are homopolymersand copolymers having a chain length such that the number of merstherein is at least two, and in some instances, as discussed below,greater than at least 3.

If two or more different oligomeric blocks are directly interconnectedthe polymers of this invention fall into the category of block polymersas defined in polymer chemistry. The polymers as defined herein can alsocontain two or more similar or identical blocks connected by a monomericor oligomeric coupling unit, with the proviso that when the blocks areidentical, the coupling unit must be copolymeric. As a result, by reasonof the coupling unit, the final material is a copolymer even thoughidentical blocks are being joined.

In more specific terms, this invention comprises two classes ofsolution-polymerized block polymers, to wit, block copolymers and chainextended copolymers. In the case of the block copolymers, they are ofthe classical A--B, A--B--A, (AB)_(n), A--B--C, etc., types. The chainextended copolymers are typically characterized by the structureA--x--A--x-- wherein A is a block unit, all the A's can be the same ordifferent and x is the chain extending monomer or dimer. When x is alarge unit, for example, an oligomer, then for the purposes of thisinvention, the polymer would be classed a block copolymer. Further, xand A must be different structural units.

Block units, according to this invention, comprise oligomeric sizestructures, i.e., structures which contain at least two monomer units insequence. Chain extending units comprise structures which are smallerthan oligomeric, i.e., they are preferably monomer and dimer structures.

The PAEKs of this invention are characterized by a toughness measured asa tensile impact strength of greater than 50 ft-lbs/in² andcrystallinity characterized by a distinct crystalline meltingtemperature (T_(m)) which is at least about 100° C. greater than itssecond order glass transition temperature (T_(g)).

It should be understood that the crystalline block copolymers of thisinvention may involve randomization due to transetherification duringthe solution polymerization reaction. Ether links formed duringpolymerization are sufficiently reactive due to activation by adjacentketone links to react with phenolic reactants and this leads to randomchain scission at the ether links adjacent to the ketone links, andre-assembling. Ether links sandwiched between two ketone links areparticularly susceptible to this scission reaction. This is well knownin the art. See Atwood et al., British Polymer Journal, 1972, Vol. 4,pp. 391-399; Atwood et al., Polymer, 1981, Vol. 22, August, pp.1096-1103. The rate of transetherification, however, is low incomparison to that of a typical nucleophilic polycondensation reaction,hence, the use of appropriate starting materials leads to thesolution-polymerized block polymers of this invention. On the otherhand, when two precursor blocks are reacted via solution-polymerizedtransetherification to yield the block copolymer, the reaction caneasily be stopped at the block copolymer stage prior to totalrandomization.

The solution-polymerized block polymers of this invention aredistinctive from those in the prior art by virtue of their enhancedlinearity. This results in polymers which posses maximum crystallinity,crystallization rates and low viscosity to high performancecharacteristics. The solution-polymerized block polymers of thisinvention are made at relatively low temperatures, typically not inexcess of 300° C. even under the most aggressive polymerizationconditions, and this is contrasted with temperatures of 400° C. whichare utilized in melt-polymerization procedures for chain extension ofpolyaryletherketones into polymer blocks (see European PatentApplication EP-125,816, supra). Consequently, solution polymerizationproceeds with minimal branching and isomerization, resulting in apolymer which provides the most favorable property characteristics.

DETAILED DESCRIPTION OF THE INVENTION

There are many varieties of PAEKs and they are made by one of twoprocesses, viz. electrophilic and nucleophilic aromatic substitutionreactions. The former is mainly achieved through Friedel-Craftscatalysis and has the advantage of allowing the use of relatively lowcost starting materials such as terephthaloyl chloride, diphenyl etherand phosgene, but suffers in the past from the necessity to employcorrosive solvents such as HF and the existence of too much branching inthe polymer structure. Nucleophilic aromatic substitution,unfortunately, requires the use of expensive fluorine substitutedmonomers such as difluorobenzophenone to achieve PAEKs with desirableproperties. Alternative routes or alternative structures which can lowerthe cost of manufacture and/or improve the polymer properties wouldprovide great advantages.

As mentioned earlier, it was found possible to adjust the T_(g) of thecopolymers to the desired level by the incorporation of units (1), (2),(3) and/or (4). Another facet of PAEK technology is that the crystallinemelting point can be fairly accurately determined from the ether to keto(or ketone) ratio in the polymer. As the ratio goes up, the T_(m) goesdown. (There is a practical limit to a suitable T_(m) ; that is thetemperature at which the polymer must be molded and the degradationtemperature of the polymer). If the molding temperature is at thedegradation temperature, and sufficient polymer flow is not obtainablebelow that temperature, then the PAEK's T_(m) is too high. This meansthat the ether-to-keto ratio is too low and must be raised. Such can beachieved by increasing the ether containing and/or forming component inthe polymer manufacture at the expense of the keto containing component.Increasing the ether content tends to increase the toughness of PAEKsand a dramatic alteration in the ether-to-keto ratio will providenoticeable changes in toughness. The tools for doing this are wellwithin the capabilities of the skilled chemist knowledgeable of thetechniques of electrophilic and nucleophilic aromatic substitutionreactions. The displacement of these groups along the linear chain ofthe polymer is not believed to be narrowly critical to achieving theT_(m) and T_(g) properties.

The Forming Reactions

One of the attributes of this invention is that the ultimate blockpolymer will be made from a PAEK starter molecule (block precursor)which is oligomeric to significantly polymeric. As a rule, the PAEKstarter molecule has a low enough molecular weight that is has a reducedviscosity below about 0.9 dl/g, as measured in concentrated sulfuricacid at 1 g/100 ml at 25° C. It is thus reacted with reactants which canform the other block or the chain extension between blocks by solutionpolymerization; indeed it is possible to combine the steps of blockpolymerization or of chain extension in the same solution polymerizationreaction. In this way, a block polymer or a chain extended polymerhaving a reduced viscosity greater than 0.9 dl/gm (as measured inconcentrated sulfuric acid at 1 g/100 ml at 25° C.) is obtainable.

An important step in the block polymer synthesis is the preparation ofthe precursor blocks. This can be done by any of the knownsolution-polymerization procedures for making PAEK, except that thestoichiometry is selected such that the precursor's molecular weight iscontrolled and the precursor is end-capped with functional groupsavailable for block copolymerization/chain extension reactions. However,if transetherification is the preferred route to block polymerformation, then the precursor need not require the presence offunctional capping groups as such. Thus, the precursor can be formedfrom conventional reactants and by using conventional methods.

For example, by the electrophilic aromatic substitution reaction, anacid halide can be reacted with a wholly functionally aromatic organiccompound to produce a host of PAEK precursor molecules. With just twomonomers and a capping agent, and using such a technique, a host ofhalide-terminated or oligomer precursors are possible. To illustratethis point, one may combine phosgene, diphenyl, terphenyl, naphthaleneor anthracene and terephthaloyl halide, with the capping agentp-fluorobenzoyl chloride, into many unique combinations. For example##STR2## Reactions A--C can be performed by conducting the twoFriedel-Crafts reactions separately. It is also possible, however, tocharge all the reagents into the reactor at once, and to thus, obtainthe dihalo-terminated oligomers in a single operation.

The above variety can be extended significantly by substituting part ofthe HPh'H with a host of other aromatic compounds, thus described byDahl and Dahl et al., supra, such as diphenyl ether, diphenoxybenzene,diphenoxybenzophenone, 4,4'-diphenoxy biphenyl,2,6-diphenoxy-naphthalene, 1,5-diphenoxy anthracene, and the like.Obviously n need not be a very large number to provide a weight averagemolecular weight which achieves a reduced viscosity of 0.9 dl/g or less.

The fact that very useful block polymers made by this invention canutilize lower molecular weight block precursors is most desirableespecially when the precursor is made by the electrophilic aromaticsubstitution reaction as above described. Such lower molecular weightprecursors are more readily washed of the catalyst such that theresulting block polymer is cleaner and less prone to unwanted branchingreactions during the final polymerization to the block polymer. It isthus an important feature of this invention that one is able to utilizeprecursors made by the electrophilic process (e.g., Friedel-Craftsreaction). Polymers with unique structures, displaying excellenttoughness and thermal stability can be prepared in this manner.

Moreover, since the precursor is not a very high molecular weightspecies, less stringent temperature conditions and thus even volatilesolvents may be used to prepare such precursor. This in turn can resultin such benefits as better color and less branching. Of course,crystallization will be an ever present problem, and temperature andsolvent selection will be dictated by this factor if the molecularweight chosen for the precursor creates such a problem. Needless to say,the options available to achieve successful polymer formation arenumerous and in no way confining to only the procedures of the prior artfor making the polymers of the prior art.

However, what is most desirable from the standpoint of PAEK manufacture,is that much of the block polymer can be derived from low cost startingmaterials such as phosgene, biphenyl, terphenyl, naphthalene,anthracene, terephthaloyl chloride, and optionally diphenyl ether.

On the other hand, the block precursor may be made according, e.g., toReactions A--C above without the fluorinated capping agent. In such acase, alteration in the stoichiometry will provide acyl halide endgroups useful for further reactions. In summary, therefore, theprecursors can be tailored such that the deisrable block polymers can beformed by both electrophilic and nucleophilic aromatic substitutionreactions. Thus, the variety of procedures for making the block polymersof this invention are many, and unconventional techniques may beavoided.

For example, the precurosrs A', B', and C' prepared as shown above canbe converted into block polymers using one or more of, for example,4,4'-difluorobenzophenone, bis-p-(p-fluorobenzoyl) benzene,hydroquinone, 4,4'-biphenol, terphenyl diol, napthalene diol, and/oranthracene diol; viz: R2 Reaction D? ? ? ? ##STR3##

It should be appreciated that transetherification as discussed abovewill make the simplistic characterization of the block polymers muchmore complex, but the overall block structure should prevail imposing asignificant structural difference from the PAEKs of the prior art.

The block precursors A--C and A'--C' above can be reacted by a furtherelectrophilic aromatic substitution reaction to produce block polymersof this invention. In the preferred practice of this invention, theblock precursors are made by either electrophilic or nucleophilicaromatic substitution reactions and the final polymerization to theblock polymer is accomplished by the nucleophlic route. An examplewherein both processes are nucleophilic is shown below: ##STR4##

The two processes, i.e., the prepolymer formation and its polymerizationto the final block- or chain-extended polymer can be performed as twoseparate steps or as a one-pot operation, wherein the intermediateoligomer is not isolated.

In summary thus, the block and chain-extended polymers of the instantinvention may contain any of the structures disclosed in U.S. Ser. No.729,580 referred to above, with the proviso, that at least one of theblocks and/or at least one of the chain-extending groups contain atleast 50 mole percent of units (1), (2), (3) and/or (4), in lieu ofunits (5).

As mentioned previously, the oligomers should generally contain at leasttwo mer units. The oligomers having repeating units (6), wherein X ishalogen or hydroxyl, ##STR5## and n is 3 or less, are disclosed in U.S.Pat. No. 3,979,459. Aromatic polyketones and copolyketone/sulfones(ketone to sulfone ratios of 75/25 to 100/0) based on (6) are describedin U.S. Pat. No. 3,928,295. The rather complicated method whereby theseoligomers are prepared is not applicable to the preparation of highermolecular weight species, i.e., those where n>3. The utility of theoligomers is obviously fully realized at higher molecular weights, atwhich the increased block lengths lead to sufficiently fastcrystallization rates, even though the glass transition temperatures ofthe segments are rather high. Hence, while the other biphenyl-,terphenyl, naphthalene and/or anthracene-based oligomers describedherein, which contain repeating units of appreciably higher molecularweights than the, molecular weight of the repeat unit of (6) are usefulfor the purposes of the instant invention even when n is only two,oligomers of the formula (6) are satisfactory at higher n values only,i.e., wherein n is at least 4 or higher. All of the oligomers can havemolecular weights of up to about 10,000.

Biphenyl-derived poly(aryl ether ketones) are also described in EuropeanPatent Application No. 194,062. The materials claimed in the subjectapplication are copolyketone/sulfones having improved glass transitiontemperatures. The presence of the SO₂ group which tends to break-up thecrystallinity of the polymer is undesirable, however; properties thatare inferior to those obtained with polymers having only ether and ketolinkages, result.

4,4'-dihydroxybiphenyl derived random poly(aryl ether ketones) aredescribed in European Patent Application Nos. 182,648 and 184,458. U.S.Pat. No. 29,489 claims halophenols of the general formula ##STR6## whereX is a halogen atom, R is O or S, and Q is CO or SO₂ ; these productsmay be used to make polymers comprising the units ##STR7## No blockpolymers or chain-extended polymers are mentioned, prepared or claimed,however.

Polymers obtained by the condensation of dihalobenzophenone with adihydroxynaphthalene alkali metal salt are described in Japanese PatentApplication No. 61/213,219. Again, no block polymers are described orclaimed.

The PAEK Block Precursors

The crystalline PAEK block precursors which are suitable for forming theblock copolymer with the exception of the end blocking portion can begenerically characterized as containing repeating units, exclusive ofthe terminating groups, of one or more of the following formulae:##STR8## wherein Ar is independently a divalent aromatic radical such asphenylene, biphenylene, terphenylene, naphthylene, or anthracenylene, Xis independently O, ##STR9## or a direct bond and n is an integer offrom 0 to 3, b, c, d and e are 0 to 1 and a is an integer of 1 to 4 andpreferably d is 0 when b is 1. It should, of course, be borne in mindthat oligomers corresponding to formula (6) must be at least tetramers.

Preferred block precursors include those having repeating units of theformulae below where Ar, Ph, and Ph' are as defined previously.##STR10## where r is less than one; and any other combinations of theunits listed above.

The most preferred Ar radicals are (1), (2), (3), (4), and (5).

The nucleophilic method comprises heating a solution of a mixture of atleast one bisphenol and at least one dihalobenzenenoid compound and/orat least one halophenol compound in which the halogen atoms areactivated by CO groups ortho or para thereto in an appropriate solventand in the presence of a base such as an alkali carbonate as describedin, for example, Canadian Pat. No. 847,963 and U.S. Pat. No. 4,176,222.In making the precursor, one of the reactants is used in excess toprovide a functional terminal group. The amount of such excess is usedto control the molecular weight of the precursor. Alternatively,equimolar amounts of reactants can be used; in such case molecularweight (or extent of reaction) is controlled by stopping the reactionafter a well-defined period of time or by using a well-defined amount ofan appropriately functionalized terminator.

Preferred bisphenols in such a process include:

4,4'-dihydroxybiphenyl, 2,6-dihydroxy naphthalene, other isomericdihydroxy naphthalene, 1,5-dihydroxy anthracene, other isomericdihydroxy anthracenes, dihydroxy terphenyls, 4,4'-dihydroxybenzophenone,and 4,4'-dihydroxydiphenyl ether.

Diphenols such as hydroquinone may also be used.

Preferred dihalobenzenoid and halophenol compounds include:

4-(4'-chlorobenzoyl)phenol,

4-(4'-fluorobenzoyl)phenol,

4,4'-bis(4"-fluorobenzoyl)diphenyl,

1,5-bis(4'-fluorobenzoyl)naphthalene,

2,6-bis(4'-fluorobenzoyl)naphthalene,

2,7-bis(4'-fluorobenzoyl)naphthalene,

2,6-2,7-bis(4'-fluorobenzoyl)anthracenes,

4,4'-difluorobenzophenone,

4,4'-dichlorobenzophenone,

4-chloro-4'-fluorobenzophenone,

1,4-bis(4'-fluorobennzoyl)benzene,

1,3-bis(4'-fluorobenzoyl)benzene, and

4,4'-bis(4"-fluorobenzoyl)diphenylether.

Also, PAEK block precursors such as those containing repeating units ofthe formula: ##STR11## where Ar, Ph and Ph' are as defined previously,may be produced as described above by Friedel-Craft reactions utilizinghydrogen fluoride-boron trifluoride catalysts as described, for example,in U.S. Pat. Nos. 3,953,400; 3,441,538; 3,442,857 and 3,516,966.

Additionally, the precursors may be prepared by Friedel-Crafts processesas described in, for example, U.S. Pat. Nos. 3,065,205; 3,419,462;3,441,538; 3,442,857; 3,516,966 and 3,666,612. In these patents, a PAEKis produced by Friedel-Crafts polymerization techniques usingFriedel-Crafts catalysts such as aluminum trichloride, zinc chloride,ferric bromide, antimony pentachloride, titanium tetrachloride, etc. anda solvent.

The precursor may also be prepared according to the processes asdescribed in, for example, U.S. Defensive Publication T-103,703 and U.S.Pat. No. 4,396,755. In such processes, reactants such as (a) an aromaticmonocarboxylic acid; (b) a mixture of at least one aromatic dicarboxylicacid, and an aromatic compound, and (c) combinations of (a) and (b) arereacted in the presence of a fluoroalkane sulphonic acid, particularlytrifluoromethane sulphonic acid.

Additionally, PAEK block precursors of the following formulas: ##STR12##may also be prepared according to the process as described in U.S. Pat.No. 4,398,020. In such a process,

(a) a mixture of substantially equimolar amounts of

(i) at least one aromatic diacyl halide of formula

    YOC--Ar.sub.1 --COY

where --AR₁ -- is a divalent aromatic radical, such as 1,4-phenylene;4,4'-biphenylene, terphenylene, naphthylene, anthracenylene, and thelike; Y is halogen, preferably chlorine, and COY is an aromaticallybound acyl halide group, which diacyl halide is polymerizable with atleast one aromatic compound of (a) (ii), and

(ii) at least one aromatic compound of the formula

    H--Ar'-H

wherein H--Ar'--H is an aromatic compound such as biphenyl, terphenyl,naphthalene, anthracene, or diphenyl ether, and H is an aromaticallybound hydrogen atom, which compound is polymerizable with at least onediacyl halide of (a)(i), or

(b) at least one aromatic monoacyl halide of the formula

    H--Ar"--COY

where H--Ar"--H is a divalent aromatic compound such as biphenyl,terphenyl, naphthalene, anthracene, diphenoxybiphenyl,diphenoxy-naphthalene, diphenoxy-anthracene, and diphenoxybenzene, and His an aromatically bound hydrogen atom, Y is halogen, preferablychlorine, and COY is an aromatically bound acyl halide group, whichmonoacyl halide is self-polymerizable, or

(c) a combination of (a) and (b) is reacted in the presence of afluoroalkane sulphonic acid.

In all of the electrophilic routes described above, the precursormolecular weight is controlled using known techniques. The preparationmay, for example, be conducted in a solvent where precipitation takesplace after a given molecular weight is reached. Control of the reactiontime is another method to control precursor size. Many other methodsexist and are well known to those skilled in the art.

The term PAEK as used herein is meant to include homopolymers,copolymers, terpolymers, graft copolymers, and the like, providedcrystallinity of the PAEK is maintained. For example, any one or more ofthe units (I) to (VI) may be combined to form copolymers, etc.

The Block Copolymers

The block copolymers may be depicted ideally as having the formula:##STR13## wherein the units A and B can be the same or different and area crystalline poly(aryl ether ketone); these units are of the formulaeshown previously; at least one of A, and/or B, and/or X must containbiphenyl, naphthalene, anthracene and/or terphenyl units; a and b areintegers of at least 2 and preferably of at least 4, with the provisothat these integers are at least 4 when oligomers of formula (6) areused; c is an integer of 1 or greater, preferably from greater than 1 upto 100, and most preferably from 3 to 90, X is a monomeric --Ar'"--O--unit where Ar'" is a divalent arylene radical such as (1), (2), (3),(4), or phenylene; X can also be an oligomeric radical such as(Ar'"--O)_(n) where n is at least two and can be up to about 50 and Ar'"is a divalent arylene group optionally containing carbonyl and/or etherfunctions in its structure, i.e., Ar'" can be, for example,4,4'-biphenylene, terphenylene, naphthylene, anthracenylene;p-phenylene, ##STR14## or --PhOPh--; finally X can be any other oligomeras described herein and in U.S. patent application Ser. No. 729,580.Where the blocks A and B are identical, X must be an oligomeric group.

The most preferred oligomers A and/or B useful for the purposes of theinstant invention are listed below; Ph and Ph' are as definedpreviously. ##STR15## Other preferred structures are those wherein partof the Ph' is replaced by Ph--O--Ph and structures combining the unitsabove, e.g., ##STR16##

In the formulae above n is at least 2, and m is at least 4; r is lessthan one. Additional preferred oligomers which may be used as either Aor B are those described in U.S. patent application, Ser. No. 729,580.

Preparation of the Block Copolymers and Oligomers

The block copolymers of this invention may be prepared by one or more ofthe following solution polymerization processes. These processes utilizeprecursors prepared as described below:

STARTING MATERIALS (I) Functionalized Starting Materials Prepared Viathe Nucleophilic Route

(A) Hydroxyl-terminated Precursors

The condensation of monomers such as listed above, i.e., the bisphenolsand dihalobenzenoids with optionally added halophenols, can be made toyield hydroxyl-terminated oligomeric precursors. The conditions used forthe preparation of these products are the same as set forth in thesection titled "Situation I", infra, except that an appropriate excessof the hydroxyl co-reactant is used. The higher the excess ofco-reactant, the lower the molecular weight of the resulting polymer.For example, a polymer having a number average molecular weight of about5,000 is obtained when one mole of diphenol is reacted with about 0.92moles of an activated dihalobenzenoid compound. A typical reaction isillustrated by the following wherein Ph and Ph' are as defined above.##STR17##

Another route to the hydroxyl-terminated precursor is the reaction of anactivated halophenol with a diphenol as shown by the following:##STR18##

B. Halogen-Terminated Precursors

A similar condensation as described in (A) above is used except that anexcess of the activated dihalobenzenoid compound is reacted. Thepreparation of the dihalo-terminated precursor is illustrated by thefollowing: ##STR19##

In another embodiment, the following approach may be used to make thedihalo-terminated oligomer: ##STR20##

Since there may be some hydrolysis during the reaction, as shown above,total dihalo termination is accomplished by adding a small additionalamount of the same dihalo compound (or optionally, any other activateddihalo compound) to the reaction mixture and heating for about 1 to 2hours.

C. Halogen-hydroxy-terminated Precursors

These precursors may be prepared by any of the following methods:

(i) Selective hydrolysis of one halo atom in (9) or (10) above, or

(ii) The reaction of equimolar amounts of diphenol and dihalo-compounds.In this case, reaction time is extremely important as it will eventuallycontrol the molecular weight of the precursor. The longer the reactiontime, the higher the molecular weight of the precursor. Shouldhydrolysis occur, termination may be carried out, as described under (B)above (i.e., via the addition of additional dihalo-compound); or

(iii) The reaction of precursor (8) with a calculated amount of adihalobenzenoid compound; or

(iv) The reaction of precursors (9) or (10) with a calculated amount ofa diphenol compound. The reaction conditions are as described underSituation I, infra. p1 (v) The self-condensation of a halophenol where,once again, the reaction time is very important since it will controlthe molecular weight of the precursor.

(II) Functionalized Materials Prepared Via The Electrophilic Route

(A) Halogen-terminated Presursors

The preparation of these materials is illustrated by the reaction ofterephthaloyl chloride and for example, biphenyl as follows: ##STR21##

Another embodiment using the same monomers is illustrated as follows:##STR22##

Still another example is provided by the reaction of phosgene with anequimolar mixture of biphenyl, terphenyl, naphthalene or anthracene withdiphenyl ether: ##STR23##

Instead of using mixtures of phosgene and of H--Ph'--H or mixtures ofphosgene and of diphenyl ether, compounds such as (15) and (16) may beemployed. ##STR24##

Thus the polyketone oligomers may be prepared by reacting an excess ofeither (i) or (ii):

(i) at least one electrophilic halo acylhalide or diacyl halide of theformula:

    YOC--A--(CO)--.sub.a --Y

where --A-- is a direct bond or a divalent aromatic radical, Y ishalogen and --COY is an acylhalide group, a is 0 or 1, and when a iszero, A must be a direct bond, polymerizable with at least one aromaticcompound of (ii) below, and

(ii) at least one aromatic compound of the formula:

    H--Ar'--H

where --Ar'-- is a divalent aromatic radical such as biphenylene,terphenylene, naphthylene, anthracenylene, diphenyl ether diyl, and thelike, and H is an aromatically bound hydrogen atom, which compound ispolymerizable with at least one halo acylhalide or diacyl halide of (i),above, accompanied or followed by the Friedel-Crafts reaction of theobtained intermediate with Z--Ar₂ H if excess of (i) is used, or withZ--Ar₂ COY if excess of (ii) is used. In the formulae above Z ishalogen, preferably fluorine, Y is as described above and Ar₂ is adivalent, optionally alkyl or aryl substituted arylene group.

Specifically, the precursors may be prepared by reacting biphenyl,terphenyl, naphthalene, or anthracene, and, optionally, in addition tobiphenyl, terphenyl, naphthalene, or anthracene, any of the well-knownaromatic co-reactants such as diphenyl sulfide, dibenzofuran, diphenylether, thianthrene, phenoxathin, dibenzodioxine, phenodioxin,diphenylene, 4,4'-diphenoxybiphenyl, xanthone, 2,2'-diphenoxybiphenyl,diphenyl methane, 1,4-diphenoxybenzene, 1,3-diphenoxybenzene,1-phenoxynaphthalene, 1,2-diphenoxynaphthalene, diphenoxybenzophenone,diphenoxy dibenzoyl benzene, 1,5-diphenoxynaphthalene,1-phenoxyanthracene, 1,5-diphenoxyanthracene, 1,6-diphenoxyanthracene,and the like. Among these, diphenyl ether, 4,4'-diphenoxybiphenyl,diphenyl methane, 1,4-diphenoxy benzene, 4,4'-diphenoxy diphenyl ether,the mono- and the diphenoxynaphthalenes, and the mono- and thediphenoxyanthracenes are preferred.

Similarly, the following compounds are diacyl halides which may be usedas reactants:

terphthaloyl chloride, isophthaloyl chloride,

thio-bis(4,4'-benzoyl chloride),

benzophenone-4,4'-di(carbonyl chloride),

oxy-bis(3,3'-benzoyl chloride),

diphenyl-3,3'-di(carbonyl chloride),

carbonyl-bis(3,3'-benzoyl chloride),

sulfonyl-bis(4,4'-benzoyl chloride),

sulfonyl-bis(3,3'-benzoyl chloride),

sulfonyl-bis(3,4'-benzoyl chloride),

thio-bis(3,4'-benzoyl chloride,

diphenyl-3,4'-di(carbonyl chloride),

oxy-bis[4,4'-(2-chlorobenzoyl chloride)],

naphthalene-1,6-di(carbonyl chloride),

naphthalene-1,5-di(carbonyl chloride),

naphthalene-2,6-di(carbonyl chloride),

oxy-bis[7,7'-naphthalene-2,2'-di(carbonyl chloride)],

thio-bis[8,8'-naphthalene-1,1'-di(carbonyl chloride)],

7,7'-binaphthyl-2,2'-di(carbonyl chloride),

diphenyl-4,4'-di(carbonyl chloride),

carbonyl-bis[7,7'-naphthalene-2,2'-di(carbonyl chloride)],

sulfonyl-bis[6,6'-naphthalene-2,2'-di(carbonyl chloride)],

dibenzofuran-2,7-di(carbonyl chloride),

anthracene-1,5-di(carbonyl chloride) and the like.

Illustrative of suitable acyldihalides include carbonyl chloride(phosgene), carbonyl bromide, carbonyl fluoride and oxaloyl chloride.

Preferably biphenyl, naphthalene, anthracene, and/or terphenylcontaining optionally some diphenyl ether, diphenoxybenzene ordiphenoxybiphenyl are reacted with terphthaloyl chloride, isophthaloylchloride and/or phosgene.

Fluorobenzene and p-fluorobenzoyl chloride, as end-capping agents, havebeen selected for illustration purposes only. It should be noted thatother similar aromatic compounds, e.g. ##STR25## and materials whereinthe fluoride is replaced by chloride, bromide, or nitro can be similarlyused.

Fluorobenzene and p-fluorobenzoyl chloride are preferred.

Self condensation of the following aromatic monoacyl halides

    H--Ar'--COY

wherein Ar' is a divalent aromatic radical such as 4,4'-biphenylene,naphthylene, anthracenylene, or terphenylene and H is an aromaticallybound hydrogen atom, Y is as defined above, and COY is an aromaticallybound acyl halide group which monoacyl halide is self-polymerizable,offers yet another route to these halo-terminated precursors. Note thatmixtures of the above H--Ar'--COY wherein at least one Ar' isbiphenylene, naphthylene, anthracenylene, or terphenylene, while theother(s) is (are) derived from any of the aromatic compounds listedabove, such as, for example, diphenyl ether, may also be used. Typicalexamples follow (Ph and Ph' are as defined previously). ##STR26##

The preferred Friedel-Crafts catalysts are aluminum chloride, antimonypentachloride and ferric chloride. Other Friedel-Crafts catalysts, suchas aluminum bromide, boron trifluoride, zinc chloride, antimonytrichloride, ferric bromide, titanium tetrachloride, and stanicchloride, can also be used. In the preferred embodiment, excess of up to100 mole percent of the acid catalyst is used.

The polymerization is generally carried out in the presence of asolvent. The preferred organic solvent is 1,2-dichloroethane. Othersolvents such as symmetrical tetrachloroethane, o-dichlorobenzene,hydrogen fluoride, methylene chloride, trichloromethane,trichloroethylene, or carbon disulfide may be employed. Cosolvents suchas nitromethane, nitropropane, dimethyol formamide, sulfolane, etc. maybe used. Concentrations as low as 3 to as high as 40 weight percent maybe used. Generally lower concentrations are preferred when highmolecular weight polymers are being prepared. Higher concentrations arepreferably used when oligomers are prepared.

The reaction may be carried out over a range of temperatures which arefrom about -40° C. to about 160° C. In general, it is preferred to carryout the reaction at a temperature in the range of -10° to about 30° C.In some cases it is advantageous to carry out the reaction attemperatures above 30° C. or below -10° C. Most preferably, thereactions are carried out at temperatures below about 0° C. Thereactions may be carried out at atmospheric pressure although higher orlower pressures may be used. Reaction times vary depending on thereactants, etc. Generally, reaction times of up to 6 hours and longerare preferred.

(B) Hydroxyl Terminated Precursors

Basic hydrolysis using methods known in the art (for example, in amixture of dimethyl sulfoxide and water, diphenyl sulfone and water,aqueous amide aprotic solvents) of the dihalo oligomers yields thedihydroxy oligomers.

(C) Hydroxyl-Halogen-Terminated Precursors

Methods very similar to those described under (I)(C) are useful, i.e.,

(i) partial hydrolysis of the dihalo-precursors,

(ii) reaction of the dihalo-precursor with a diphenol under nucleophilicsubstitution conditions.

(iii) reaction of the dihydroxy precursor with an activateddihalobenzenoid compound under conditions of nucleophilic substitution.

(III) Non-functionalized Precursors

Using the Friedel-Crafts reaction described above, non-functionalizedprecursors can be prepared. An example is shown: ##STR27## Anothernon-functionalized oligomer is, for example, (19a). ##STR28##

Obviously, a wide variety of such oligomers are possible by theappropriate selection of the monomers listed above.

PREPARATION OF THE BLOCK COPOLYMERS Situation (I)

The block copolymers may be prepared by a nucleophilic reaction betweenpreformed precursors or polymers having mutually reactive groups asfollows:

    nA+nB→(AB).sub.n

there may be more than two precursors or polymers, used to form theblock copolymers, i.e.,:

    nA+nB+nC→(ABC).sub.n

The precursors or polymers may be illustrated by the following:

    X˜A--X

where X is a halogen attached to an aromatic carbon atom, preferablychlorine or fluorine; X is located in a position ortho or para to##STR29## and by

    HO˜B˜OH

The reaction of these two precursors or polymers forms the blockcopolymer (AB)_(n). Alternatively, the precursors or polymers may beillustrated by the following:

    HO˜A˜X, and

    HO˜B˜X

The condensation of the two blocks shown above leads to a blockcopolymer. In another alternative, two oligomers of the formulae

    X˜A˜X, and

    X˜B˜X

are condensed with a monomeric material, i.e.,

    HO--monomer--OH

to give the copolymer; or

    HO˜A˜OH, and

    HO˜B˜OH

can be reacted with the dihalo-monomer

    X--monomer--X

to yield the copolymer.

If A and B are identical, their coupling (e.g., the last two cases) mustbe performed with a difunctional oligomeric agent, i.e.,:

    HO˜OLIGOMER˜OH

or

    X˜OLIGOMER˜X

Specific examples follow: ##STR30##

The precursors (20) and (21) are prepared using the nucleophilic route.Electrophilically prepared, fluorine-terminated starting materials areshown below: ##STR31## The preparation of oligomeric coupling agents isillustrated below: ##STR32## The equation below illustrates the couplingof two identical blocks using an oligomeric agent: ##STR33## Otheruseful oligomers are, for example, (26), (27), and (28), all preparednucleophilically, using an ##STR34## excess of 4,4'-difluorobenzophenonewith hydroquinone, 4,4'-biphenol, and 2,6-naphthalenediol. The reactionof (26) with (27) or with (28), and an equimolar amount of eitherhydroquinone or 4,4'-dihydroxydiphenyl ether will yield coupled polymershaving different blocks wherein one of the blocks does not contain abiphenyl, a naphthalene, an anthracene, or a terphenyl residue.

These nucleophilic polycondensation reactions are carried out by heatinga mixture of the said precursor or precursors with the appropriatemonomers (if required) at a temperature of from about 100° to about 400°C. The reactions are conducted in the presence of an alkali metalcarbonate or bicarbonate. Preferably a mixture of alkali metalcarbonates or bicarbonates is used. When a mixture of alkali metalcarbonates or bicarbonates is used, the mixture comprises sodiumcarbonate or bicarbonate with a second alkali metal carbonate orbicarbonate wherein the alkali metal of the second carbonate orbicarbonate has a higher atomic number than that of sodium. The amountof the second alkali metal carbonate or bicarbonate is such that thereis from 0.01 to about 0.25 gram atoms of the second alkali metal pergram atom of sodium. Of course, it is possible to use the preferredalkali metal salts of diphenols.

The higher alkali metal carbonates or bicarbonates are thus selectedfrom the group consisting of potassium, rubidium and cesium carbonatesand bicarbonates. Preferred combinations are sodium carbonate orbicarbonate with potassium carbonate or cesium carbonate.

The alkali metal carbonates or bicarbonates should be anhydrousalthough, if hydrated salts are employed, where the polymerizationtemperature is relatively low, e.g., 100° to 250° C., the water shouldbe removed, e.g., by heating under reduced pressure, prior to reachingthe polymerization temperature.

Where high polymerization temperatures (>250° C.) are used, it is notnecessary to dehydrate the carbonate or bicarbonate first as any wateris driven off rapidly before it can adversely affect the course of thepolymerization reaction.

The total amount of alkali metal carbonate or bicarbonate employedshould be such that there is at least one atom of alkali metal for eachphenol group. Hence, when using an oligomeric diphenol there should beat least one mole of carbonate, or two moles of bicarbonate, per mole ofthe aromatic diol. Likewise where an oligomeric halophenol is employedthere should be at least 0.5 mole of carbonate, or one mole ofbicarbonate, per mole of the halophenol.

An excess of carbonate or bicarbonate may be employed. Hence there maybe 1 to 1.2 atoms of alkali metal per phenol group. While the use of anexcess of carbonate or bicarbonate may give rise to faster reactions,there is the attendant risk of cleavage of the resulting polymer,particularly when using high temperatures and/or the more activecarbonates.

As stated above, the amount of the second (higher) alkali metalcarbonate or bicarbonate employed, is such that there are 0.001 to about0.2 gram atoms of the alkali metal of higher atomic number per gram atomof sodium.

Thus, when using a mixture of carbonates, e.g., sodium carbonate andcesium carbonate, there should be 0.1 to about 20 moles of cesiumcarbonate per 100 moles of sodium carbonate. Likewise, when using amixture of a bicarbonate and a carbonate, e.g., sodium bicarbonate andpotassium carbonate, there should be 0.05 to 10 moles of potassiumcarbonate per 100 moles of sodium bicarbonate.

A mixed carbonate, for example sodium and potassium carbonate, may beemployed as the second alkali metal carbonate. In this case, where oneof the alkali metal atoms of the mixed carbonate is sodium, the amountof sodium in the mixed carbonate should be added to that in the sodiumcarbonate when determining the amount of mixed carbonate to be employed.

Preferably, from 0.001 to 0.2 gram atoms of the alkali metal of thesecond alkali metal carbonate or bicarbonate per gram atom of sodium isused.

Where an oligomeric bisphenol and oligomeric dihalobenzenoid compoundare employed, they should be used in substantially equimolar amounts. Anexcess of one over the other leads to the production of lower molecularweight products. However, a slight excess, up to 5 mole percent, of thedihalide or of the bisphenol, may be employed, if desired.

The reaction is carried out in the presence of an inert solvent.Preferably, the solvent is an aliphatic or aromatic sulphoxide orsulphone of the following formula ##STR35## here x is 1 or 2 and R andR' are alkyl or aryl groups and may be the same or different. R and R'may together form a divalent radical. Preferred solvents includedimethyl sulphoxide, dimethyl sulphone, sulpholane (1,1 dioxothiolan),or aromatic sulphones of the formula: ##STR36## where R₂ is a directlink, an oxygen atom or two hydrogen atoms (one attached to each benzenering) and R₃ and R'₃, which may be the same or different, are hydrogenatoms and alkyl or phenyl groups. Examples of such aromatic sulphonesinclude diphenylsulphone, dibenzothiophen dioxide, phenoxathiin dioxideand 4-phenylsulphonyl biphenyl. Diphenylsulphone is the preferredsolvent. Other solvents that may be used include benzophenone,N,N-dimethyl acetamide, N,N-dimethyl formamide andN-methyl-2-pyrrolidone.

The polymerization temperature is in the range of from about 100° toabout 400° C. and will depend on the nature of the reactants and thesolvent. The preferred temperature is above 270° C. The reactions aregenerally performed under atmospheric pressure. However, higher or lowerpressures may be used.

For the production of some polymers, it may be desirable to commencepolymerization at one temperature, e.g., between 200° and 250° C. and toincrease the temperature as polymerization ensues. This is particularlynecessary when making polymers having only a low solubility in thesolvent. Thus, it is desirable to increase the temperature progressivelyto maintain the polymer in solution as its molecular weight increases.

To minimize cleavage reactions, it is preferred that the maximumpolymerization temperature be below 350° C.

The polymerization reaction may be terminated by mixing a suitable endcapping reagent, e.g., a mono or polyfunctional halide such as methylchloride, difluorobenzophenone, monofluoro benzophenone,4,4'-dichlorodiphenylsulphone with the reaction mixture at thepolymerization temperature, heating for a period of up to one hour atthe polymerization temperature and then discontinuing thepolymerization.

This invention is also directed to an improved process for making theblock and chain-extended polymers. Specifically, this process isdirected to preparing poly(aryl ether ketone) precursors and the blockpolymers by the reaction of a mixture of at least one bisphenol and atleast one dihalobenzenoid compound, and/or a halophenol to make theprecursor, or the reaction of the precursors to make the block polymerseither one or both in the presence of a combination of sodium carbonateand/or bicarbonate and an alkali metal halide selected from potassium,rubidium, or cesium fluoride or chloride, or combinations thereof.

The reaction is carried out by heating a mixture of one or morebisphenols and one or more dihalobenzenoid compounds and/or halophenolsor the block precursors and other reactants, as described herein, at atemperature of from about 100° to about 400° C. The reaction isconducted in the presence of added sodium carbonate and/or bicarbonateand potassium, rubidium or cesium fluorides or chlorides. The sodiumcabonate or bicarbonate and the chloride and fluoride salts should beanhydrous although, if hydrated salts are employed, where the reactiontemperature is relatively low, e.g., 100° C. to 250° C., the watershould be removed, e.g., by heating under reduced pressure, prior toreaching the reaction temperature.

Where high reaction temperatures (>250° C.) are used, it is notnecessary to dehydrate the carbonate or bicarbonate first as any wateris driven off rapidly before it can adversely affect the course of thereaction. Optionally, an entraining organic medium can be used to removewater from the reaction mixture such as toluene, xylene, chlorobenzene,and the like.

The total amount of sodium carbonate or bicarbonate and potassium,rubidium or cesium fluoride or chloride, or combinations thereofemployed should be such that there is at least one atom of total alkalimetal for each phenol group, regardless of the anion (carbonate,bicarbonate or halide). Likewise, where a halophenol is employed, thereshould be at least one mole of total alkali metal per mole ofhalophenol.

Preferably, from about 1 to about 1.2 atoms of sodium for each phenolgroup are used. In another preferred embodiment, from 0.001 to about 0.5atoms of alkali metal (derived from a higher alkali metal halide) areused for each phenol group.

The sodium carbonate or bicarbonate and potassium fluoride are used suchtht the ratio of potassium to sodium therein is from about 0.001 toabout 0.5, preferably from about 0.01 to about 0.25, and most preferablyfrom about 0.02 to about 0.20.

An excess of total alkali metal may be employed. Hence, there may beabout 1 to about 1.7 atoms of alkali metal per phenol group. While theuse of a large excess of alkali metal may give rise to faster reactions,there is the attendant risk of cleavage of the resulting polymer,particularly when using high temperatures and/or the more active alkalimetal salts. In this respect, cesium is a more active metal andpotassium is a less active metal so that less cesium and more potassiumare used. Further, the chloride salts are less active than the fluoridesalts so that more chloride and less fluoride is used.

Where a bisphenol and dihalobenzenoid compound are employed, they shouldbe used in substantially equimolar amounts when maximum molecular weightis sought. However, a slight excess, up to 5 mole percent of thedihalide or of the bisphenol, may be employed if desired. An excess ofone over the other leads to the production of low molecular weightproducts which can be desirable when the process is directed to makinglower molecular weight PAEK, for example, the precursors for blockpolymer formation.

The reactions are carried out in the presence of an inert solvent. Thesolvents that are useful are the same as those described for thereactions utilizing sodium carbonate or bicarbonate in combination witha second alkali metal carbonate or bicarbonate.

The reaction temperature is in the range of from about 100° to about400° C. and will depend on the nature of the reactants and the solvent.The preferred temperaure is above 250° C. The reactions are preferablycarried out at ambient pressure. However, higher or lower pressures canalso be used. The reaction is generally caried out in an inertatmosphere.

For the production of some block polymers, it may be desirable tocommence reaction at one temperature, e.g., between 200° and 250° C. andto increase the temperature as reaction ensues. This is particularlynecessary when making high molecular weight polymers having only a lowsolubility in the solvent. Thus, there it is desirable to increase thetemperature progressively to maintain the polymer in solution as itsmolecular weight increases.

This invention is also directed to an improved process for making thepoly(aryl ether ketone) oligomers and the chain-extended and blockpolymers gel-free and at very high reaction rates. These polymerizationsare performed in the presence of a base which is composed of sodiumcarbonate or bicarbonate and of a potassium, rubidium, or cesium salt ofan organic acid.

Salts of any organic acid are useful. Thus, one may use the potassium,rubidium, or cesium salts of aliphatic linear or branched acids such asformic, acetic, propionic, butyric, isobutyric, pentanoic, hexanoic,heptanoic, octanoic, nonanoic, decanoic, 2-methyl-butyric,3,4-dimethyl-pentanoic, 4,4-dimethyl hexanoic, 2-ethyl-heptanoic,3-propyl-5,6-dimethyl nonanoic and other similar acids.

Salts of halo-substituted aliphatic acids such as monochloro-,dichloro-, and trichloroacetic, 2-chloropropionic,3,5-dichloroheptanoic, bromacetic, 3-fluorobutyric, and3,3,3-trichloropropionic acids.

Salts of aromatic mono- or polynuclear acids such as benzoic, toluic,3,4-dimethylbenzoic, 2-chlorobenzoic, 3,4-dichlorobenzoic,2-bromobenzoic, 2-chloro-4-methylbenzoic, 2-fluoro-3-ethylbenzoic, otheralkyl and/or halo-substituted benzoic acids, the naphthalene carboxylicacids, alkyl-substituted naphthalene carboxylic acids such as3-methylnaphthalene-1-carboxylic acid, 6-ethyl-naphthalene-2-carboxylicacid, halo-substituted naphthalene carboxylic acids such as4-chloro-naphthalene-2-carboxylic acid, phenanthrene and anthracenecarboxylic acids and the like.

Salts of araliphatic acids such as phenylacetic, diphenyl acetic,1-naphthyl acetic, 2-naphthyl-acetic, 4-chlorophenyl acetic,4-methylphenyl acetic, 3-bromo-1-naphthyl acetic,4-chloro-2-naphthyl-acetic, 3-(6-chloro-1-naphthyl)propionic,3-(4-ethylphenyl)butyric, 3-methyl-4-(2-ethyl-4-chlorophenyl)butyric,3-phenyl-hexanoic, and 7-phenylnonanoic acids.

Salts of heterocyclic carboxylic acids such as furane-2-carboxylic,furane-3-carboxylic, thiophene-2-carboxylic, thiophene-3-carboxylic, thepyridine, quinoline and isoquinoline carboxylic acids.

Salts of alkyl, aryl, and halo-substituted heterocyclic acids such as2-methylfurane-3-carboxylic, 4-chloro-pyridine-2-carboxylic,2-methyl-4-oxazole carboxylic and 2-propyl-pyrazine-3-carboxylic acids.

Salts of dicarboxylic acids such as oxalic, malonic, succinic, adipic,suberic, azelaic, α-bromo-glutaric,β,β'-dimethyl-glutaric,α,α'-dichlorosuberic, maleic and fumaric acids.

Salts of aromatic and heterocyclic dicarboxylic acids such as phthalic,isophthalic, terephthalic, naphthalene-1,2-dicarboxylic,naphthalene-2,3-dicarboxylic, naphthalene-1,5; 1,6; 1,7; 1,8; 2,4; 2,5;and 2,6-dicarboxylic, pyridine-2,3-dicarboxylic, furane-2,3-dicarboxylicacids and the like.

Salts of aliphatic, aromatic, and heterocyclic sulfonic and sulfinicacids such as methane sulfonic, ethane sulfonic, propane sulfonic,benzene sulfonic, benzene sulfinic, 1-naphthalene sulfonic,2-naphthalene sulfonic, 1-naphthalene sulfinic, 1,8-naphthalenedisulfonic, 2,6-naphthalene disulfonic, 4-methyl-benzene sulfinic,p-toluene sulfonic, 3,4-dichloro-benzene sulfonic,6-chloro-naphthalene-1-sulfonic, quinoline-2-sulfonic, 4-pyridinesulfonic, 2-thiophene sulfonic, 3-thiophene sulfonic, 3-methyl-2-furanesulfinic, 3-propyl-2-furane-sulfonic acids and the like.

Salts of aliphatic, aromatic and heterocyclic phosphonic and phosphinicacids such as methane phosphonic, ethane phosphonic, benzene phosphinic,benzene phosphonic, 1-naphthalene phosphonic, 2-naphthalene-phosphonic,1-naphthalene-phosphinic, 1,8-naphthalene diphosphonic, 2,6-naphthalenediphosphonic, 4-methyl-benzene phosphinic, 4-ethyl-benzene phosphonic,3,4-dichloro-benzene phosphonic, 3,4-dibromobenzene phosphonic,3-chloro-4-methyl benzene phosphonic, 6-chloro-1-naphthalene phosphonic,2-quinoline-phosphonic, 2-thiophene phosphonic, 3-thiophene phosphonic,3-thiophene phosphinic, 3-chloro-2-furane phosphinic, 3-propyl-2-furanephosphonic acids and the like.

Mixed salts such as for example, mixtures of potassium and rubidiumacetates or mixtures of potassium acetate and potassium benzenesulfonate, and the like can also be used. The preferred salts arepotassium formate, acetate, propionate, oxalate, benzoate, benzenesulfonate and p-toluene sulfonate.

The reaction is carried out by heating a mixture of one or moremonomeric and/or oligomeric bisphenols and one or more monomeric and/oroligomeric dihalobenzenoid compounds and/or halophenols at a temperatureof from about 100° to about 400° C. The reaction is conducted in thepresence of added sodium carbonate and/or bicarbonate and potassium,rubidium or cesium salts of an organic acid, vide ultra. The sodiumcarbonate or bicarbonate and the organic salts should be anhydrousalthough, if hydrated salts are employed where the reaction temperatureis relatively low, e.g., 100° to 250° C., the water should be removed,e.g., by heating under reduced pressure, prior to reaching the reactiontemperature.

Where high reaction temperatures (>250° C.) are used, it is notnecessary to dehydrate the carbonate or bicarbonate first, as any wateris driven off rapidly before it can adversely affect the course of thereaction. Optionally, an entraining organic medium can be used to removewater from the reaction such as toluene, xylene, chlorobenzene, and thelike.

The total amount of sodium carbonate and/or bicarbonate and potassium,rubidium or cesium organic salt employed should be such that there is atleast one atom of total alkali metal for each phenol group, regardlessof the anion (carbonate, bicarbonate and of the organic acid). Likewise,where a halophenol is employed, there should be at least one mole oftotal alkali metal per mole of halophenol.

Preferably, from about 1 to about 1.2 atoms of sodium for each phenolgroup is used. In another preferred embodiment, from 0.001 to about 0.5atoms of alkali metal (derived from the alkali metal organic salt) isused for each phenol group.

The sodium carbonate or bicarbonate and the potassium organic salt areused such that the ratio of the potassium to sodium therein is fromabout 0.001 to about 0.5, preferably from about 0.001 to about 0.20 andmost preferably from about 0.01 to about 0.1.

An excess of total alkali metal may be employed. Hence, there may beabout 1 to about 1.7 atoms of alkali metal per phenol group. While theuse of a large excess of alkali metal may give rise to faster reactions,there is the attendant risk of cleavage of the resulting polymer,particularly when using high temperatures and/or the more active alkalimetal salts. Of course it is well known to those skilled in the art thatcesium is a more active metal and potassium is a less active metal sothat less cesium and more potassium are used. It is preferred that theratio of carbonate and bicarbonate anions to the phenolic groups beabout 0.5 to 1.0 respectively. However, higher and lower ratios are alsopossible.

Where a bisphenol and dihalobenzenoid compound are employed, whethermonomeric or oligomeric, they should be used in substantially equimolaramounts when maximum molecular weight is sought. In other words, thetotal number of moles of phenolic groups should be the same as the totalnumber of halo atoms. However, a slight excess of up to 5 mole percentof the dihalide or of the diphenol, may be employed if desired. Anexcess of one over the other leads to the production of low molecularweight products which is the case when oligomers useful for thecopolymers of the instant invention are being prepared via thenucleophilic route.

The reaction is carried out in the presence of a solvent. The solvent ispreferably an aliphatic or aromatic sulphoxide or sulfone of the formula##STR37## where x is 1 or 2 and R and R' are alkyl or aryl groups andmay be the same or different. R and R' may together form a divalentradical. Preferred solvents include dimethyl sulphoxide, dimethylsulphone, sulpholane (1,1 dioxothiolan), or aromatic sulphones of theformula ##STR38## where R₂ is a direct link, an oxygen atom or twohydrogen atoms (one attached to each benzene ring) and R₃ and R'₃, whichmay be the same or different, are hydrogen atoms or phenyl groups.Examples of such aromatic sulphones include diphenylsulphone, ditolylsulphone, tolylphenyl sulphone, dibenzothiophen dioxide, phenoxathiindioxide and 4-phenylsulphonyl biphenyl. Diphenylsulphone is thepreferred solvent.

The reaction temperature is in the range of from about 100° to about400° C. and will depend on the nature of the reactants and solvent. Thepreferred temperature is above 250° C. The reactions are preferablycarried out at ambient pressure. However, higher or lower pressures canalso be used. The reaction is generally carried out in an inertatmosphere.

For the production of some poly(aryl ether ketones), it may be desirableto commence reaction at one temperature, e.g., between 200° and 250° C.and to increase the temperature as reaction ensues. This is particularlynecessary when making high molecular weight polymers having only a lowsolubility in the solvent. Thus, there it is desirable to increase thetemperature progressively to maintain the polylmer in solution as itsmolecular weight increases.

Situation (II)

The block copolymers of this invention may be prepared by a nucleophilicpolycondensation reaction between a precursor or polymer and one or moremonomers.

The various combinations possible in this situation are illustratedbelow:

    HO˜A˜OH                                        II.a.

is reacted with

    X--monomer--X+HO--monomer--OH

to give the block copolymer; or

    X˜A˜X                                          II.b.

is reacted with

    X--monomer--X+HO--monomer--OH

to yield the block copolymer.

II.c. Still another possibility is the following:

    HO˜A˜OH

is reacted with

    X--monomer--OH

or

    X˜A˜OH

is reacted with

    X--monomer--X

and

    HO--monomer--OH

or

    X˜A˜X

is reacted with

    X--monomer--OH

or

    X˜A˜OH

is reacted with

    X--monomer--OH.

II.d. Triblock copolymers could, for instance, be obtained via the routeshown:

    X˜A˜X+

    HO˜B˜OH+X--monomer--OH.

Diblock copolymers will be obtained via the above scheme if A and B havethe same composition, or if the polymer block obtained fromX--monomer--OH is identical to one of the precursors.

Numerous other possibilities that are obvious to those skilled in theart exist.

Additionally, the block copolymer may be prepared from a preformedpolymer and an oligomer via coupling and transetherification. Theprocess conditions in Situation II are the same as discussed forSituation I.

Situation (III)

The block copolymers of this invention may also be prepared by theFriedel-Crafts (electrophilic) polymerization techniques as fullydescribed above. The preparation of a block copolymer (AB)_(n) based onbiphenyl (H--Ph--Ph--H), diphenyl ether and terphthaloyl chloride isillustrated in (a) below; a similar block copolymer made from phosgeneand from terphthaloyl chloride is shown in (b). ##STR39##

The acid chloride terminated oligomer (31) and the "hydrocarbonterminated oligomer (32) are used similarly to form the analogousnaphthalene-containing block copolymers. ##STR40##

In all cases steps 1 and 2 can be performed separately or in a one-potoperation.

Situation IV

Poly(ether ketone) based block copolymers can be prepared using anon-functionalized oligomers such as (19) or (19a) for example. Bothnucleophilic and electrophilic (Friedel-Crafts) condensations arepossible.

(a). The Nucleophilic Polycondensation

The solution condensation of hydroquinone and 4,4'-difluorobenzophenonein the presence of oligomer (19) will yield a copolymer due to atransetherification process accompanying polymer formation. This isschematically represented as follows: ##STR41##

There are numerous possibilities for reagent selection; hence, thenumber of structures that are available is very wide.

(b). Electrophilic (Friedel-Crafts) Polycondensation

Oligomers (19) (19a), or any other non-functional oligomer of theformula ##STR42## wherein Ar and Ar' are divalent aromatic radicals aspreviously defined; Ar₃ is a monovalent aromatic group such asphenoxyphenyl or biphenylyl and the like; can be condensed in aFriedel-Crafts reaction with a reactive aromatic hydrocarbon and adicarboxylic acid or dicarboxylic acid halide. Two illustrative examplesare shown: ##STR43##

Obviously, once again, numerous possibilities exist and are obvious tothose skilled in the art.

The copolymers of this invention may include mineral fillers such ascarbonates including chalk, calcite and dolomite; silicates, includingmica, talc, wollastonite; silicon dioxide; glass spheres; glass powders;aluminum, clay; quartz; and the like. Also, reinforcing fibers such asfiberglass, carbon filters, organic polyamide fibers, and the like maybe used. The copolymers may also include additives such as titaniumdioxide; thermal stabilizers, ultraviolet light stabilizers, processingaids, placticizers, and the like.

The copolymers of this invention may be fabricated into any desiredshape, i.e., moldings, coatings, films or fibers. They are particularlydesirable for use as electrical insulation for electrical conductors.

Also, the copolymers may be woven into monofilament threads which arethen formed into industrial fabrics by methods well known in the art asexemplified by U.S. Pat. No. 4,359,501. Further, the copolymers may beused to mold gears, bearings and the like.

EXAMPLES

The following examples serve to give specific illustrations of thepractice of this invention but they are not intended in any way to limitthe scope of the invention.

EXAMPLE 1 Preparation of a difluoro-terminated biphenyl-based poly(arylketone) oligomer via the electrophilic route

A 500 ml 4-necked flask was fitted with a mechanical stirrer, refluxcondenser, thermometer, nitrogen sparge, solids addition funnel and gasoutlet tube connected to an aqueous sodium hydroxide trap. The apparatuswas charged with

217.0 ml of 1,2-dichloroethane,

37.01 g (0.24 moles) of biphenyl,

40.60 g (0.20 moles) of terephthaloyl chloride, and

12.68 g (0.008 moles) of p-fluorobenzoyl chloride.

The mixture was cooled to 0° C. as 89.60 g (0.67 moles) of aluminumtrichloride was added at such a rate as not to exceed 5° C. After 6hours at 0° C., the reaction mixture was coagulated into 500 ml ofpreheated (to 80° C.) water. The slurry was then heated to 100° C.,stirred for 15 minutes, filtered, and the precipitate washed with water(twice; each wash: 300 ml of water, 5 minutes) and once with methanol(300 ml, 5 minutes). The final purification was achieved by reslurryingthe material in refluxing methanolic hydrogen chloride (567 ml ofmethanol and 33 ml of concentrated HCl) for 1.5 hours, followed byfiltration and washing with water (twice, 300 ml each time, 5 minutes)and with methanol (300 ml, 5 minutes). The final oligomer, having thestructural formula shown, had a reduced viscosity of 0.16 dl/g (1 g/ 100ml concentrated sulfuric acid, at 25° C.). ##STR44##

EXAMPLE 2 Nucelophilic preparation of a dihydroxy-terminated oligomerand its coupling to a block copolymer

A 250 ml flask was fitted with a mechanical stirrer, thermocouple,nitrogen sparge, Claisen adapter, Dean-Stark trap and a pressureequalizing dropping funnel. The apparatus was charged with

68.00 g of diphenyl sulfone,

3.30 g (0.030 moles) of hydroquinone,

5.89 g (0.027 moles) of 4,4'-difluorobenzophenone,

6.16 g (0.058 moles) of sodium carbonate,

0.42 g (0.003 moles) of potassium carbonate, and

25 ml of xylene.

The atmosphere in the apparatus was evacuated and the apparatus wascharged with nitrogen. This operation was repeated three times. A flowof nitrogen was maintained in the apparatus throughout the experiment.The mixture was heated to 200° C. for 30 minutes, then to 250° C. for 30minutes and finally to 300° C. After one hour, a sample was takenfollowed by the addition of 5.59 g (0.030 moles) of 4,4'-biphenol and10.64 g (0.033 moles) of 1,4-bis(p-fluorobenzoyl)benzene. After 15minutes the reaction mixture was poured hot from the reactor, allowed tosolidify and ground finely. The product was refluxed in acetone (2times; 200 ml of acetone used each time; reflux time: 1.5 hours); water(2 times, 700 ml of water used each time; reflux time: 1.5 hours), andagain once in acetone (700 ml of acetone, 1.5 hours). The sample takenprior to the addition of 4,4'-biphenol and1,4-bis(p-fluorobenzoyl)benzene was worked-up in a similar manner. Thereduced viscosities of the sample and of the final polymer (1 g/100 mlconcentrated H₂ SO₄ ; 25° C.) were 0.35 and 0.51, respectively.

DSC analysis of the block polymer (rate of heating=10° C. per minute)indicated that the material had, as expected, two melting points, at323.4° C. and at 420.8° C., respectively.

What is claimed is:
 1. A crystalline, tough poly(aryl ether ketone)solution polymerized block polymer comprising a block of a polymercontaining ether groups joined to keto groups through units of at leastone formulae selected from the group consisting of ##STR45## which blockis bonded to another block through one or more of an ether group, a ketogroup or a divalent chain extending single or oligomeric unit, with theproviso that when the blocks are identical, then the coupling group iscopolymeric.
 2. The crystalline, tough poly(aryl ether ketone) of claim1 wherein the toughness thereof is measured as a tensile impact strengthof greater than 50 ft.lbs./in².
 3. The crystalline, tough poly(arylether ketone) of claim 1 wherein the crystallinity thereof ischaracterized by a distinct crystalling melting temperature which is atleast 100° C. greater than its second order transition temperature.
 4. Acrystalline tough poly(aryl ether ketone) block or chain extendedpolymer having the formula ##STR46## wherein A and B are a crystallinepoly(aryl ether ketone), a and b are integers of at least 2; c is aninteger of 1 or greater; d is 0 or 1; X is either a monomeric--Ar'"--O-- unit where Ar'" is a divalent arylene radical, or anoligomeric radical, with the proviso that if either A and B contains theunits ##STR47## a or b must be at least 4; and with the additionalproviso that when A and B are identical, X is an oligomeric radical. 5.A polymer as defined in claim 4 wherein at least one of the blocks A andB or the chain-extending group X contain at least 50 mole percent ofunits selected from the group consisting of ##STR48##
 6. A polymer asdefined in claims 4 or 5 wherein Ar'" is selected from the group of##STR49## and the oligomeric radical is (--Ar""--O--)_(n), wherein n isat least two to about 50, and Ar"" is a divalent arylene group.
 7. Thecrystalline poly(aryl ether ketone) of claims 1 or 4 or 5 which containsrepeating units of one or more of the following formulae: ##STR50##wherein Ar is independently a divalent aromatic radical selected fromphenylene, biphenylene, terphenylene, naphthylene or anthracenylene, Xis independently O, ##STR51## or a direct bond and n is an integer offrom 0 to 3; b, c, d and e are 0 to 1 and a is an integer of 1 to
 4. 8.The crystalline poly(aryl ether ketone) of claim 7 which containsrepeating units of one or more of the following formulae: ##STR52##wherein Ar is independently a divalent aromatic radical selected fromphenylene, biphenylene, terephenylene, naphthylene or anthracenylene; Phis 1,4-phenylene with the proviso that where there are two carbonylgroups attached to the same Ph, up to 50 mole percent of these groupscan be in the 1,3 position to each other; Ph' is independentlybiphenylene, terphenylene, naphthylene or anthracenylene; and r is lessthan
 1. 9. A polymer as defined in claim 4 of the following formula:##STR53## where x and y are one or greater.
 10. A polymer as defined inclaim 4 of the following formula: ##STR54##
 11. A polymer as defined inclaim 4 of the following formula: ##STR55##
 12. A polymer as defined inclaim 4 of the following formula: ##STR56##
 13. A polymer as defined inclaim 4 of the following formula: ##STR57##
 14. A polymer as defined inclaim 4 of the following formula: ##STR58##
 15. A polymer as defined inclaim 4 of the following formula: ##STR59## wherein Ph--Ph isbiphenylene and Ph--Ph--Ph is terphenylene.
 16. A polymer as defined inclaim 4, prepared by the nucleophilic polycondensation of the oligomers:##STR60## with hydroquinone.
 17. A polymer as defined in claim 4,prepared by the nucelophilic polycondensation of the oligomers:##STR61## with 4,4'-dihydroxydiphenyl ether.
 18. A polymer as defined inclaim 4, prepared by the nucelophilic polycondensation of the oligomers:##STR62## with hydroquinone.
 19. A polymer as defined in claim 4,prepared by the nucelophilic polycondensation of the oligomers:##STR63## with 4,4'-dihydroxydiphenyl ether.
 20. A polymer as defined inclaim 4, prepared by the Friedel-Crafts catalyzed polycondensation ofthe oligomer ##STR64## with diphenyl ether and terephthaloyl chloride.21. A polymer as defined in claim 4, prepared by the Friedel-Craftscatalyzed polycondensation of the oligomer ##STR65## with diphenyl etherand terephthaloyl chloride.
 22. A polymer as defined in claim 4,prepared by the Friedel-Crafts catalyzed polycondensation of theoligomer ##STR66## with diphenyl ether and terephthaloyl chloride.
 23. Apolymer as defined in claim 4, prepared by the Friedel-Crafts catalyzedpolycondensation of the oligomer ##STR67## with diphenyl ether andterephthaloyl chloride.
 24. A polymer as defined in claim 4, prepared bythe high-temperature nucelophilic polycondensation of the oligomer##STR68## with hydroquinone and 4,4'-difluorobenzophenone.
 25. A polymeras defined in claim 4, obtained by the Friedel-Crafts catalyzedpolycondensation of the oligomer: ##STR69## with diphenoxybiphenyl andterephthaloyl chloride.
 26. A polymer as defined in claim 4, obtained bythe Friedel-Crafts catalyzed polycondensation of the oligomer: ##STR70##with diphenyl ether and phosgene.
 27. The block copolymer of claim 1wherein a block with a polymer containing ether groups is joined to ketogroups also through units of the formulae ##STR71##
 28. The polymer ofclaim 6 wherein Ar"" comprises a divalent arylene group containing acarbonyl or an ether function in its structure.